One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,7)(8,12)(14,17)(18,20)(21,22)(23,28)(24,26)(25,27) involution — undirected(5,6,9,7)(8,11,12,10)(21,22,26,24)(23,27,25,28)(6,7)(10,11)(13,14)(15,18)(16,17)(19,20)(21,23,26,25)(22,27,24,28)(1,2,3,4)(5,7,9,6)(8,11,12,10)(13,14)(15,18)(16,17)(19,20)(21,24,26,22)(23,27,25,28)(5,8)(6,10)(7,11)(9,12)(13,15,16,19)(14,18,17,20)(21,25,26,23)(22,27,24,28)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.